Question: Rewrite as a simplified fraction. ${3.9\overline{28} = {?}}$
Solution: Let $x$ equal the decimal. Set up two equations such that the digits after the decimal point are identical. ${\begin{align*}1000x &= 3928.2828...\\ 10x &= 39.2828...\end{align*}}$ Subtracting the two equations, we have: ${990x = 3889}$ ${x = \dfrac{3889}{990}} \text{or} {3 \dfrac{919}{990}}$